


The Martian

by FirebirdsDaughter



Category: Kamen Rider Build
Genre: Gen, Original Kamen Rider, Pandora - Freeform, This is actually set pretty early in the series, don't know how many chapters there will be, i don't know why i didn't post it when I originally wrote it?, lots of robot destruction
Language: English
Status: In-Progress
Published: 2018-01-24
Updated: 2018-01-25
Packaged: 2019-03-08 18:54:08
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,571
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13464435
Author URL: https://archiveofourown.org/users/FirebirdsDaughter/pseuds/FirebirdsDaughter
Summary: A mysterious new Rider enters the field, one drastically different than Build, or even Nightrogue and Blood Stalk.The strange newcomer claims to be Pandora--and demands the Box be returned...





	1. Arrival

**Author's Note:**

> So... I wrote that thing w/ Pandora before, and then never posted anything else.  
> But I did write it?  
> This is set earlier in the season, before things went to, well, shit.  
> Enjoy?

**Summary for the Chapter:**

> Pandora makes themselves known.

     Ryuuga was starting to wonder when he’d learn. After all, he’d yet to do anything that **didn’t** end in disaster, which Sento regularly reminded him of—which hadn’t stopped them from ending up surrounded by Guardians again, not to mention a very pissed off Gentoku. He immediately regretted allowing himself to get distracted when one of the robots popped out of nowhere in front of him, preparing to strike. On instinct, he ducked his head, throwing his arms up to cover it, braving for impact. That never came. He peeked out from under his arm.

     The robot had frozen, it’s weapon raised just centimetres above Ryuuga’s head. Cautiously, the former pro fighter lowered his arms, then instinctively began to look around for Sento… Only to find Build several yards away, just as surprised beneath his mask. Sputters and sparks made him look down to see an armoured hand protruding from the thing’s chest. It gave another jolt, then the hand retreated, allowing the machine to collapse to the ground.

     Standing before him was another Rider—or, something Rider-like—broad shouldered and sturdy. Like Build, the suit was layered, but with three colours instead of two, twisted instead of striped; sheafs of darkest black and a brilliant crimson that matched the light from the top of the Sky Walls were intertwined with a line that blazed the same burning azure colour as the Box in the photos Sento brought back from the lab. Up close, Ryuuga could see similar patterns to the ones engraved in the panel they kept in the base beneath a sleek black robe that shone rainbow like raven feathers, secured at both corners to the right shoulder, concealing most of the body, and most specifically, whatever Driver was being used.

     There was a distinct style to the suit that was unlike Build’s; the eyes were smaller, shaped and glowing like fiery embers, outlined in gold, with a raised edge atop the head that looked strangely like a plume, the rest shaped like an ancient helmet, the ends of which disappeared behind the folds of the cloak collar. A small breeze rustled the cloak, brushing it aside enough to show a similar armour-like design underneath it, despite the twisted colours. An elegant chest plate gave way to a tunic hem of the same material as the mantle, below which were a set of greaves upon multicoloured boots; the arm that retreated back into the robe was gauntleted, the borders also gilded with gold, and the un-plated parts were a shiny, leathery red gold. When the newcomer folded their arms, the robe was finally fully moved, revealing the belt and Driver. That was also drastically different from Sento’s—it looked distinctly old fashioned, dark and worn. There was a wheel on the side rather than a crank, and the whole thing was more compact and simple.

     The greatest difference, however, was the third Full Bottle.

     Two of them were set the same way that Build’s were, side by side, an impossibly deep black and vivid red one. Neither were marked like the ones Misora created, and had a slightly different shape. The third one, however, was even more exotic; it glowed, like the Box and luminescent parts of the suit, and deep, impossibly blue hue. It was even smaller than the other Bottles, more cubic, and was set into the side of the top of the Driver, right in the middle.

     Eventually, the awed silence was broken by Gentoku.

     “Who are you?” His hand shifted just a little, and more Guardians shuffled forward into defensive positions.

     After a moment’s pause, the new arrival turned slowly, unfolding their arms, chin high. When they spoke, it was with a deep, slightly distorted voice that sounded a little like Nightrogue or Blood Stalk’s; but, strangely, not as frightening. “… You have the honour of addressing Pandora, Keeper of the Temples. Now… Return my Box!” The last part was accented by a flourishing point. From the corner of his eye, Ryuuga saw Sento getting to his feet, transfixed by the newcomer.

     Pandora. Pandora’s Box. Even Ryuuga could make that connection.

     Evidently, however, the Aide couldn’t, or really felt like playing dumb to someone who had just destroyed one of his robot soldiers with a single hand. “I have no idea what you’re talking about.” He sighed loudly, folding his own arms. “In fact, you just destroyed government property in defence of a fugitive, so I also have no reason to negotiate with you.”

     Pandora seemed unperturbed by his tone, and simply spoke again as if he hadn’t answered. “You **will** return my Box to me. As for the matter of your machine…”  The stranger cast a single glance towards the Guardian, than looked even more casually at Ryuuga before turning back. “… My senses have told me this human is innocent of your charge. I cannot speak for anything else, however.”

     “Innocent? What do you mean?” The question came from Utsumi, who received a glare from his boss for the interruption.

     “My people have the ability to detect deception and falsehoods. The Dragon Human is not lying.”

     It took Ryuuga a moment to realise he’d just been referred to as ‘the Dragon Human.’ “Oi! What’s that supposed to mean?” Pandora didn’t even look back, just pointed over his shoulder; turning, he discovered that the little dragon mech Sento had made was hovering there curiously.

     Pandora, however, was not interested in it or him. “I have graced this planet with my presence in order to retrieve that which was stolen. You will give it to me now so that I may return to my home and continue my vigil.”

     Gentoku studied the stranger for a long time, then sighed again, a little differently this time. “I don’t just have it with me,” He began, one hand behind his back as he started to pace—the Guardians moved in time, but it didn’t seem like they were just getting out of his way, “We would have to go and get it from the lab, which would be a hassle… It might be easier if you… Came back with us?”

     Pandora, however, apparently did not trust the robots’ movements anymore than the human they had just saved, as Ryuuga saw the mysterious newcomer shifting cautiously from his place close behind them. “… Know your place, human, and know to whom you speak. You will bring my Box **to** me. My greatness shall not go anywhere **with** you.”

     Gentoku clicked his fingers, and the Guardians swarmed.

     None of them survived the assault.

     Something that could have been a hand or a small meteorite connected with Ryuuga’s chest, sending him careening away from the fray—he probably would have busted something on the land of Sento hadn’t surprised him by catching him. In the middle of a mess of machines, Pandora was moving faster than the eye could see; fighting purely barehanded, though there were occasional flashes of amber light that might have come from punches or kicks the same way the Dragon or Rabbit Bottles lit up him and Sento respectively. It was over in moments—what had once been a fight became a proud, gleaming figure standing in a pile of scrap.

     Pandora’s head tilted, and though they could not see the face beneath, Ryuuga felt the disappointment in his bones like it was his own. “I had hoped for more… Cooperation.” The stranger heaved a sigh themselves. “Very well. I shall recover my Box myself.” Reaching down, Pandora tapped the darker Bottle, then spun the wheel on their Driver, and a voice completely different from the Build Driver declared ‘ **NEBULA**! **COSMIC CLOUD**!’

     Glittering black smoke erupted from the black Bottle, surrounding not only Pandora, but Build and Ryuuga as well. Despite the fighter’s bewilderment, Sento took the opportunity to load them both onto the bike and take off. A glance back as the cloud cleared revealed that Pandora had also used the cover to escape, vanishing without a trace.


	2. Interim

**Summary for the Chapter:**

> Fall back, regroup, and think.  
> Meanwhile, two old ~~enemies~~ acquaintances meet once more.

**Notes for the Chapter:**

> So this was on my mind?  
> If I have any layover between the two, I'm actually part way through the next chapter of You Can't Take The Sky From Me. So hopefully that'll be up in the next couple days, if I have time--my schedule is both solidifying and getting a little busier, so I'm writing when I can. ^^;

     “… Why’d he cover us, too?”

     Sento shrugged, sitting back at his workbench in the base while Ryuuga paced and mused. “Maybe as a gift—a thanks for being honest when they weren’t.”

     Ryuuga only grunted in reply, because at that moment, they were interrupted by Sawa, who rushed down the stairs waving a set of photos, closely followed by Souichi. At the noise, Misora groggily set up and snarled, but uncharacteristically did not attack.

     “I found him!” Sawa shrieked excitedly, skidding to a halt in the middle of the room. “I found more on Pandora!”

     With his usual abnormal speed when his interest was piqued, Sento was instantly beside her, peering at the photos. “What about him?”

     “Well, apparently he’s made a few appearances to some regular people before he showed himself to you guys and the government.” She handed him a pair of photographs—poor, blurry ones, but the subject was visibly Pandora. “Apparently, people have been seeing him around—like some sort of ghost or something. But heres the thing, according to one witness I talked to, he was seen single-handedly—and I mean with **one hand** —taking down…” Her voice became hushed like she thought she was on a movie set, “… A **Smash**!’

     “A Smash showed up and we didn’t hear about?” Souichi had joined them at the reporter’s elbow.

     “Could be he took it out so fast you didn’t pick it up. Apparently he’s a real badass.” With an excited squeal, she turned back to Sento. “Looks like you have some headline competition—Kamen Rider Pandora!”

     Sento let out a huff and shoved the pictures back to her. “You can’t go calling him a Kamen Rider just because he saved a couple people.” He muttered, sounding just a little affronted. “Besides, we don’t actually know his motives. Sure, he helped us today, but is he going to keep doing that?”

     Souichi moved to lean against the wall, folding his arms and frowning. “I’m actually with Sento on this. Could be they’re just pretending to be a hero.” He was abruptly startled from his feigned ‘suaveness’ by his phone going off. “Ah! Gotta go to work!” He dashed off, nearly tripping on the stairs as he went.

     Sawa ignored him, instead following Sento over to his desk. “Why are you against Pandora being an ally? Wouldn’t it be nice to have some help?”

     “I don’t need help. And I especially don’t need someone trying to take my hero position.”

     Ryuuga groaned, rolling his eyes. “Of course it’s that.” He walked over to Sento’s other side to prod the physicist’s shoulder. “You didn’t seem so upset when he first showed up.”

     Sento huffed, dropping what he was working on onto his desk with a thunk. “I was interested in the suit, not the person. It’s irritating that I can’t seem to figure either how it’s created, or where those Bottles came from.” He spun his chair around, forcing the two of them to jump backwards to avoid being hit by his knees. Pulling out the Tank FullBottle, he held it up. “See. These are the normal FullBottles.” Getting up, he grabbed one of the tighter-framed photo’s from Sawa’s hand and slammed it against the whiteboard—or tried to, because in his frustration, he set the whole thing spinning and had to dodge it, then grab and stop it, finally just taping the picture up and holding the Bottle up next to it. “You can even tell from this out-of-focus image that the Bottles in that Driver are different.” He turned, squinting at the photo. “Not to mention the Driver itself. Who made it? Why? When? Why are they just showing up now? If they’re here to help, why didn’t they come earlier?”

     “The thing did look kinda old.” Ryuuga admitted. “Like… Dusty, actually.”

     “Okay,” Sawa said, and almost clapped her hands together before remembering Misora was a sleep in the bed and just clasped them quietly. “So a new Rider with an old Driver. Maybe they found it?”

     “Where?” Ryuuga snorted. “Mars?” When both Sawa and Sento went very quiet, he blinked, looking between them nervously. “What? What did I say?”

     Sento, however, had his ‘thinking face’ on. “I can’t believe I…” He yanked the photo off the board, squinting at it, then shoving it into his pocket. “I have to go to the lab.”

     “What is going on?” Ryuuga demanded again, only to be ignored once more as Sento scrambled to acquire his jacket.

     “Gotta go, gotta go,” Sento hummed to himself, then pause, turning to Sawa. “Can you-”

     “I’ll find the inventory for the _Prominence_ mission before and after.” She said excitedly, and rushed ahead of him. Sento started bobbing up the steps after her.

     “Oi!” Ryuuga growled, hurrying over to grab his ear and drag him back down, taking a second to duck under a half-hearted flailing arm. “What’d I say?”

     Sento sighed dramatically. “Mars, you oaf. Seriously, you had an ever closer look at the Driver than I did. It wasn’t just dusty—it was **red** dust. Not a hue commonly seen on Earth either.” He righted his clothes, though Ryuuga’s grabbing him hadn’t actually ruffled them. “Combined with the apparent age, it’s not a far hypothesis that the Box might not have been the only thing the _Prominence_ brought back.” Then he darted away before Ryuuga could demand further explanation—though the former pro-fighter tried anyway.

     “How do you-”

     He was abruptly cut off by a pillow smacking him in the back of the head, and quickly retreated under Misora’s glare.

* * *

     They found each other quite easily, tracking one another through some multi-century old instinct. They weren’t very happy to see the other, either.

     “I thought you were dead.” Blood Stalk drawled, sitting atop a wall with his legs crossed, bouncing a foot.

     “More like you hoped.” Pandora replied cooly.

     Stalk laughed unnaturally. “Oh, we both know how I feel about hope.”

     “Ah, yes.” Even with a distorted voice, it was plain Pandora was rolling their eyes. “Of course! How could I forget. Only good for crushing.”

     “What are you even doing here?”

     “Shouldn’t that be obvious to you, of all…” The last part trailed off, and Pandora turned to look up at Stalk with folded arms. “… I think the better question is what do **you** think you’re doing here?”

     “The same thing I do everywhere.”

     “How comforting.” Pandora replied sarcastically. “But there is no place here for someone like you.”

     “You’re overestimating humans.”

     “They are no more flawed than my kind were.”

     “Agree to disagree.”

     “Did you just compliment my species? **You**?” There was another long silence between them when Stalk didn’t answer, which Pandora eventually broke again. “I will not allow history to repeat. I will stop you.”

     “Maybe. But I don’t think you have it in you.”

     “Have you forgotten whose Box it is?”

     “No. But you’re a Keeper, a Guardian. A protector.” Stalk got to his feet, balancing easily on the wall. “So I don’t think you’ll risk harming the human that might still be in here.”

     “… Coward.”

     “Hardly, just clever.” He waved cheerily at them. “Ta-ta, Princess.” Then he turned and jumped down the other side of the wall, leaving behind the rather unhappy Rider.

     “I am **not** a princess,” Pandora growled, but rolled their shoulders to activate the boosters on the back of their suit, hovering into the air, and then soaring off in the opposite direction.

**Notes for the Chapter:**

> Can you, uh, tell what my Blood Stalk theory is? At all? Can you?  
> Why yes, I'm very comfortable here in potential denial while probably setting myself up for disappointment.
> 
> Yes, most of the crew is calling Pandora 'he.'  
>  ~~(bc they're dumdums)~~  
>  In other news, I figured out strikethrough on here.


End file.
